Field of the Disclosure
Embodiments of the present invention relate to an organic light emitting display device, and more particularly, to a top emission type organic light emitting display device.
Discussion of the Related Art
An organic light emitting display (OLED) device, which is a self light emitting display device, has advantages of low power consumption, rapid response speed, high emission efficiency, high luminance, and wide viewing angle.
According to a direction of light emitted from an organic light emitting device, the OLED device may be largely classified into a top emission type and a bottom emission type. In case of the bottom emission type, a circuit device is disposed between an emitting layer and an image displaying surface, whereby an aperture ratio may be lowered due to the circuit device. Meanwhile, in case of the top emission type, a circuit device is not disposed between an emitting layer and an image displaying surface, whereby an aperture ratio may be improved.
FIG. 1 is a cross sectional view of a related art top emission type OLED device.
As shown in FIG. 1, a thin film transistor layer (T) including an active layer 11, a gate insulating film 12, a gate electrode 13, an insulating interlayer 14, a source electrode 15, and a drain electrode 16 is provided on an active area of a substrate 10, and then a passivation layer 20 and a planarization layer 30 are sequentially provided on the thin film transistor layer (T).
Also, an anode electrode 40 and an auxiliary electrode 50 are provided on the planarization layer 30. The auxiliary electrode 50 is provided to reduce a resistance of a cathode electrode 80 to be explained later.
On the anode electrode 40 and the auxiliary electrode 50, a bank 60 is provided to define a pixel region. Also, an organic emitting layer 70 is provided in the pixel region defined by the bank 60, and the cathode electrode 80 is provided on the organic emitting layer 70.
In case of the top emission type, light emitted from the organic emitting layer 70 passes through the cathode electrode 80. In this reason, the cathode electrode 80 is formed of a transparent conductive material, which causes the increase of resistance therein. In order to reduce the resistance of the cathode electrode 80, the cathode electrode 80 is connected with the auxiliary electrode 50.
The gate insulating film 12 is provided on a pad area of the substrate 10, a first signal pad 90 is provided on the gate insulating film 12, and the insulating interlayer 14 is provided on the first signal pad 90.
A second signal pad 95 is provided on the insulating interlayer 14. The second signal pad 95 is connected with the first signal pad 90 via a contact hole provided in the insulating interlayer 14.
The passivation layer 20 is provided on the second signal pad 95, and a hole is provided in the passivation layer 20. Through the hole provided in the passivation layer 20, the second signal pad 95 is exposed externally. In order to connect the second signal pad 95 with an external driving circuit, the hole is provided in the passivation layer 20, and the second signal pad 95 is exposed externally.
In order to overcome a problem relating to a corrosion of the second signal pad 95 in the related art top emission type organic light emitting display device of FIG. 1, pad electrodes for covering the second signal pad 95 are provided. However, if applying the pad electrodes, a bonding process of the pad area may be difficult.